Vacuum Pump going south!?!?!?!?!?! - PeachParts Mercedes-Benz Forum

jcd · #1 09-20-2002, 01:51 PM

OK here's the symptoms.

Noticed a new squeak coming from the engine compartment. I can hear it from the drivers compartment, but not when I look under the hood....may be unrelated.

I noticed that the engine was slow to shut down......door locks work, no other vacuum issues.

Then............the brakes were very hard to compress, but only after I have to hit them a couple of times, i.e. first hit on the brake pedal, normal, if I hit the brakes a couple of more times, the pedal gets firmer and firmer and the brake action is not as strong. PS, new pads, new master cylinder, new fluid as of a couple of months ago.

HELP

JCD

leathermang · #2 09-20-2002, 02:35 PM

The squeak is the famous New Jersey One Eyed Rat Tailed Squirrel... it lives under the dash, thus no noise present in the engine compartment...

The other probably is your vacuum pump going south or an intermittant leak in the lines...

jcd · #3 09-20-2002, 03:51 PM

I checked vacuum at the line that T's off the line to the brake booster, it pulled 6 pounds. I seem to remember that it should pull around 20 pounds...................

Wait a minute...................BAM............killed the squirrel.

Anyway...... do you think that it is the valve or the diaphram...or do I need to pull it apart to check it out.

JCD

leathermang · #4 09-20-2002, 04:31 PM

If you have never replaced your diaphram... it does not cost much and it is one of those insurance deals.. one less thing to catch you off from the house gone wrong... the actual diaphram itself I think is only about $10.. or the complete kit about $36...Go for it I say... no use worrying about it.....

leathermang · #5 09-20-2002, 04:33 PM

UH, I forgot to mention those squirrels are on the endangered species list.. You should have been able to guess that since that was the first one you ever saw....

jcd · #6 09-20-2002, 07:55 PM

Greg......

We have enough black bears up here that they are regular diners on garbage cans, kitchens and stealing groceries out of cars. It's a mess.......my feeling is, any species in my yard is endangered.

I ordered both the vacuum valves and the diaphram from Fastlane. Thought,,,,,,,,, do you have to remove the entire vacuum pump to replace the valves and diaphram, or can you just remove the "front end; of the vacuum pump that contains the valves and the diaphram and replace them without removing the entire housing. It looks like you can remove the front end without removing the entire housing. My Dad, the PO, said that he had a heck of a time getting the gasket to seal when he took off the entire vacuum pump. His suggestion was just to remove the "front end", replace the diaphram and the valves.

Thoughts.

PS,,,,,,,,,I love animals.......just not in my yard.

JCD

#7 09-20-2002, 08:03 PM

I have a feeling you've just got a big vacuum leak somewhere from a cracked line or rubber connector. The vacuum pump's weren't issues in these cars.

leathermang · #8 09-20-2002, 10:57 PM

On a 25 year old car the item does not have to be "an issue " to need replacing.... if there is a question it seems good insurance to replace a rubber item every quarter of a century

Just as one might replace radiator hoses and belts every couple of years... just on principle....

JCD, I live in the country... I agree with your policy.....

When my vacuum pump gave way TCane was here and doing FAQ pictures.. he had the diaphram and only replaced that.. it fixed it... so I don't know about the other item parts in the kit...I have the pics I could share...

#9 09-20-2002, 11:02 PM

I didn't know the vac pumps were any concern on these cars, I have never heard of many going bad, but I do know on the newer 60x engines you only get about 150k out of them.

I would still check how well the vacuum holds in the rest of the system before tearing out the vacuum pump. It could be something simpler.

jcd · #10 09-21-2002, 07:21 AM

In fact, this is the second time. My dad had to replace the valves in the vacuum pump XXX years ago. Thankfully, he replaced all of the hoses and belts as well.

I did a pretty thorough vacuum check and it is isolated to the pump.

Question: Can you just remove the front of the vacuum pump, i.e. from the diaphram out, replace the diaphram and the valves and put it back. This would allow me to "rebuild" vacuum pump without removing the main housing. My Dad had that suggestion. He had a heck of a time replacing the vacuum pump housing without having it leak and he thought that just removing the front end of the pump would avoid this problem.

JCD

leathermang · #11 09-21-2002, 08:32 AM

JCD, I do not know which type vacuum pump you have.. here is a picture of the one on my 1980 240... which was repaired with it on the engine and from the front...

leathermang · #12 09-21-2002, 08:34 AM

Here it is fixed....

jcd · #13 09-21-2002, 10:03 AM

I have the same kind of pump. That was the approach that I was going to take. It looks alot easier than removing the entire vacuum pump housing.

I'm also going to replace the valves while I have it off.

Any tricks and about how long did it take.

This site is the best.

JCD

leathermang · #14 09-21-2002, 11:07 AM

I was just taking pictures on this,,, TCane was going to write up the procedure for the FAQ pages...
It took less than two hours...
You will need a spanner to hold the round plate visible in the pic.. while you turn the allen (?) head bolt in the center...then you will put the new diaphram in... but the engine/pump plunger must be in a proper position when you install.... and I am not sure how to determine that... I do think the Haynes and FSM's have good instructions... but I was just watching Tom....and pestering him about letting me get more pics...
I do think, if possible , that it is much better to do it from the front...

leathermang · #15 09-21-2002, 11:14 AM

Here are C-clip plyers (being used as spanner wrench) , allen head wrench and locater screws all at once..